Withdrawal/ infeed of gas for influencing radial liquid migration

ABSTRACT

The invention relates to a heat exchanger for indirect heat exchange between a first medium and a second medium, comprising a shell surrounding a shell space which extends along a longitudinal axis. The shell space serves for accommodating the first medium. A tube bundle is arranged in the shell space having multiple tubes for accommodating the second medium. The tubes are helically coiled in multiple tube layers onto a core tube. The tube bundle has a multiplicity of inner tube layers, surrounding the core tube, and a multiplicity of outer tube layers, surrounding the inner tube layers. The heat exchanger discharges a part of a gaseous phase out of the shell space from the region of the inner tube layers via a gas discharge device, and/or supplies a gaseous phase into the shell space in the region of the outer tube layers via a gas supply device.

The invention relates to a coiled heat exchanger according to Claim 1.

Such coiled heat exchangers are used for example in the case of physicalquenches for acid gas removal (e.g. Rectisol processes), in ethyleneplants or in plants for producing liquefied natural gas (LNG).

Liquid on the shell side of such heat exchangers with falling filmevaporation is, in most cases, diverted in the direction of the outertube layers of the tube bundle. This incorrect distribution of theliquid leads to a local deficit in the supply of coolant to the tubebundle in the region of the inner tube layers of the tube bundle, andtherefore to losses in performance of the heat exchanger.

Taking this as a starting point, it is therefore the object of thepresent invention to provide a coiled heat exchanger which counteractssuch performance losses.

This object is achieved by a heat exchanger having the features of claim1 and by a method having the features of claim 14. Advantageousrefinements of these aspects of the present invention are specified inthe corresponding subclaims and will be described below.

According to claim 1, a heat exchanger for the indirect exchange of heatbetween a first medium, which has a liquid phase and a gaseous phase,and a second medium is disclosed, having

-   -   a shell which surrounds a shell space and which extends along a        longitudinal axis, wherein the shell space serves for        accommodating the first medium, and    -   a tube bundle which is arranged in the shell space and which has        multiple tubes for accommodating the second medium, which tubes        are helically coiled in multiple tube layers onto a core tube of        the heat exchanger, which tube bundle extends along the        longitudinal axis of the shell in the shell space, wherein the        tube bundle has a multiplicity of inner tube layers, which        surround the core tube, and a multiplicity of outer tube layers,        which surround the inner tube layers and the core tube.

It is now provided according to the invention that the heat exchangerhas a gas discharge device by means of which a part of the gaseous phasecan be discharged out of the shell space from the region of the innertube layers, wherein the gas discharge device of the heat exchanger hasat least one discharging flow path for the gaseous phase with an inletopening arranged in the shell space in the region of the inner tubelayers, and wherein the at least one discharging flow path is formed bya tube of an inner tube layer of the tube bundle, in particular by atube of an innermost tube layer of the tube bundle (or has such an inneror innermost tube).

Alternatively or in addition, provision is made according to theinvention for the heat exchanger to have a gas supply device via which agaseous phase of the first medium can be supplied into the shell spacein the region of the outer tube layers.

The tube bundle coiled onto the core tube has, as viewed in a radialdirection, a multiplicity n of tube layers situated one on top of theother, wherein, in the case of an even number n of tube layers,proceeding from the core tube, all tube layers up to the n/2-th tubelayer are understood in the context of the invention to be inner tubelayers, whereas the tube layers that follow these toward the outside(that is to say from the (n/2+1)-th tube layer to the n-th tube layer)are regarded as outer tube layers. In the case of an odd number of tubelayers, the inner (n−1)/2 two players are understood to be inner tubelayers, and the remaining tube layers are understood to be outer tubelayers.

In one embodiment of the invention, the discharge of the gaseous phasetakes place in the region of the innermost tube layer, and the supply ofthe gaseous phase takes place in the region of the outermost tube layer.

Owing to the invention, it is advantageously possible for a pressuredrop in a radial direction of the tube bundle (outward toward the shell)to be reduced or avoided, such that a pressure which is as far aspossible constant in a radial direction prevails in the shell space.This increases the effectiveness of the heat exchanger, because theabovementioned deflection of the liquid is reduced or avoided in thisway.

In the present case, the radial direction of the tube bundle refers to adirection which is perpendicular to the longitudinal axis of the shelland which points outward toward the shell, whereas the axial directioncoincides with the longitudinal axis. The core tube is preferablyarranged in the shell space coaxially with respect to the longitudinalaxis, and correspondingly extends in the axial direction.

The liquid phase can in a known manner be applied to the tube bundlefrom the top. Here, a liquid distributor used for distributing theliquid phase can also at the same time perform a separation of theliquid phase from the gaseous phase of the first medium. The separationof the liquid phase from the gaseous phase may however also be performedin separate units. The liquid distributor can conduct the liquid phasefor example via an encircling gap on the shell, or via tubes, into aring-shaped channel which is situated therebelow and which hasdistributor arms. Alternatively, the liquid phase can be introduced viaa central opening into the core tube and then conducted to a distributorin the form of a pressure distributor. Such liquid distributors aredescribed in detail for example in DE 10 2004 040 974 A1. Other liquiddistributors are likewise conceivable.

Furthermore, in one embodiment of the heat exchanger according to theinvention, it is conceivable for the at least one discharging flow pathto run, at least in sections, in the core tube, for example instead of adischarging flow path, which is formed by a tube of an inner tube layerof the tube bundle, in particular by a tube of an innermost tube layerof the tube bundle (see also above).

In the case of a discharging flow path which is led at least in sectionsin the core tube, the inlet opening may be formed in the wall of thecore tube. Alternatively, the discharging flow path may be led through awall of the core tube, wherein the inlet opening is arranged outside thecore tube in the region of the inner tube layers, or terminates flushwith a surface of the wall of the core tube. Furthermore, the inletopening may be arranged, in a radial direction of the tube bundle,between the surface of the wall of the core tube and an innermost tubelayer.

It is basically possible for the at least one discharging flow path tobe formed by a tube line.

Furthermore, in the case of a discharging flow path formed by a tube ofan inner or of the innermost tube layer, the inlet opening may be formedin particular in a wall of the respective tube.

Furthermore, in one embodiment of the heat exchanger according to theinvention, provision is made for the heat exchanger to have a skirtsurrounding the tube bundle, which skirt surrounds the outer tubelayers. Such a skirt may have a hollow cylindrical form and serve toprevent a bypass flow of the first medium past the tube bundle in theshell space. For this purpose, the skirt preferably engages tightlyaround the tube bundle.

Furthermore, in a preferred embodiment of the heat exchanger accordingto the invention, provision is made for the heat exchanger or the gassupply device to have, for supplying a gaseous phase of the firstmedium, at least one supplying flow path which has an outlet openingwhich is arranged in the shell space, or opens into the shell space, inthe region of the outer tube layers.

In one embodiment of the heat exchanger according to the invention,provision is made here for the at least one supplying flow path to beled at least in sections on an outwardly pointing outer side of theskirt (that is to say runs further to the outside, in a radialdirection, than the skirt, such that there, the skirt runs between thetube bundle and the supplying flow path) or is formed by a tube of anouter tube layer of the tube bundle, in particular by a tube of anoutermost tube layer of the tube bundle (or has such an outer oroutermost tube).

In the case of a supplying flow path which is led at least in sectionson the outer side of the skirt, the outlet opening may be formed in theskirt. Alternatively, the supplying flow path may be led through theskirt, wherein the outlet opening may be arranged, within a shell spacesection surrounded by the skirt, in the region of the outer tube layers,or may terminate flush with an inner side of the skirt. Furthermore, theoutlet opening may be arranged, in a radial direction of the tubebundle, between the inner side of the skirt and an outermost tube layer.

It is basically possible for the at least one supplying flow path to beformed for example by a tube line.

Furthermore, in one embodiment of the heat exchanger according to theinvention, provision is made for the heat exchanger or the gas dischargedevice to have multiple discharging flow paths for the gaseous phase ofthe first medium within each case one inlet opening, wherein the inletopenings are each arranged in the shell space in the region of the innertube layers. It is furthermore preferable for the inlet openings to bearranged at different heights along the longitudinal axis. Theindividual inlet openings may in this case be formed in accordance withone of the variants mentioned above.

In a further embodiment of the heat exchanger according to theinvention, provision is preferably made for the heat exchanger or thegas supply device of the heat exchanger to have multiple supplying flowpaths for the gaseous phase of the first medium with in each case oneoutlet opening, wherein the outlet openings are each arranged in theregion of the outer tube layers in the shell space, and wherein, inparticular, the outlet openings are arranged at different heights alongthe longitudinal axis.

In particular, a tube or a tube line which constitutes a discharging ora supplying flow path may have multiple inlet or outlet openings, whichare for example arranged one behind the other along the respective tubeor the respective tube line. In this way, it is possible in each casefor a multiplicity of flow paths to the respective inlet or outletopening to be provided by means of a single tube or a single tube line.It is self-evidently also possible for a separate tube or a separatetube line to be provided for each inlet or outlet opening.

In a further embodiment of the heat exchanger according to theinvention, provision is preferably made for the heat exchanger to bedesigned to control the supply of the gaseous phase via the gas supplydevice and/or the discharge of the gaseous phase via the gas dischargedevice in open-loop fashion, or in closed-loop fashion in a mannerdependent on an actual pressure distribution measured in the shell spaceor an actual temperature distribution measured in the shell space.

It is to be noted here that the temperature distribution in the shellspace changes in accordance with the pressure distribution, such thatthe temperature distribution is also suitable for the closed-loopcontrol of the gas discharge or supply.

In the case of closed-loop control, provision may be made in particularfor the heat exchanger to control the supply and/or discharge of thegaseous phase in closed-loop fashion such that the actual pressuredistribution in the shell space is approximated to a setpoint pressuredistribution and/or such that the actual temperature distribution isapproximated to a setpoint temperature distribution, wherein, inparticular, the pressure of the setpoint pressure distribution is ineach case constant in a radial direction of the tube bundle, andwherein, in particular, the temperature of the setpoint temperaturedistribution is in each case constant in a radial direction,specifically in particular in each case at least at a defined height ofthe shell space (e.g. at the level of the discharge and/or supply of thegaseous phase) or in a defined shell space section along thelongitudinal axis of the shell.

In one embodiment, the heat exchanger is preferably configured suchthat, over the entire length of the tube bundle along the longitudinalaxis, a part of the gaseous phase can be discharged from the region ofthe inner tube layers via a multiplicity of inlet openings, and/or thegaseous phase of the first medium can, in the region of the outer tubelayers, be supplied via a multiplicity of outlet openings, such that, inparticular over the entire length of the tube bundle, the actualpressure distribution or the actual temperature distribution isapproximated to a setpoint pressure distribution or setpoint temperaturedistribution respectively, in the case of which the pressure or thetemperature respectively is in each case preferably constant in a radialdirection and follows a predefined or desired profile in an axialdirection (that is to say along the longitudinal axis).

The heat exchanger according to the invention may have the sensorsdescribed further below for the purposes of measuring an actual pressuredistribution or an actual temperature distribution.

Furthermore, in one embodiment of the heat exchanger according to theinvention, provision is made for the at least one discharging flow pathor the gas discharge device to have a valve for the open-loop orclosed-loop control of the discharge of the gaseous phase.

In the same way, the at least one supplying flow path or the gas supplydevice may have a valve for the open-loop or closed-loop control of thesupply of the gaseous phase.

In a further embodiment of the heat exchanger according to theinvention, provision is made for the at least one discharging flow pathto be connected or connectable in terms of flow via a compressor, inparticular a compressor which is controllable in open-loop orclosed-loop fashion, to the at least one supplying flow path. In thisway, a gaseous phase discharged out of the shell space from the innerlayers of the tube bundle can, after corresponding compression, besupplied to the shell space again in the region of the outer tube layersin a variable manner or in a manner controllable in open-loop orclosed-loop fashion.

Furthermore, in one embodiment of the heat exchanger according to theinvention, provision is made for the individual tube layers to bearagainst one another via spacers. The core tube preferably accommodatesthe load of the tubes of the tube bundle, wherein, in particular, theload of the tube layers is dissipated inward via the respective spacers.

In a further embodiment of the heat exchanger according to theinvention, provision is made for the heat exchanger to have a firstline, via which the first medium is introducible (in particular intwo-phase form) into the heat exchanger or the shell space, and/or forthe heat exchanger to have a second line, via which the first medium iswithdrawable from the heat exchanger or from the shell space of the heatexchanger.

The first line may for example be connected to a connector of the heatexchanger (for example at an upper section of the heat exchanger). Thesecond line may likewise be connected to a connector of the heatexchanger (for example at a lower section of the heat exchanger).

In a further embodiment, the heat exchanger has a first flow connectionbetween the gas discharge device and the first line, such that a gaseousphase of the first medium or a process flow is withdrawable from the gasdischarge device, and introducible into the first line, via the firstflow connection.

Furthermore, in a further embodiment, the heat exchanger may also have afirst flow connection between the gas discharge device and the secondline, such that the a gaseous phase of the first medium or a processflow is withdrawable from the gas discharge device, and introducibleinto the second line, via the first flow connection.

Furthermore, in one embodiment of the invention, provision is made forthe heat exchanger to have a second flow connection between the gassupply device and the first line, such that the a gaseous phase of thefirst medium or a process flow can be introduced from the first lineinto the gas supply device via the second flow connection.

Furthermore, in a further embodiment, the heat exchanger may also have asecond flow connection between the gas supply device and the secondline, such that a gaseous phase of the first medium or a process flowcan be introduced from the second line into the gas supply device viathe second flow connection.

Furthermore, in one embodiment, the first flow connection may alsoconnect the gas discharge device to the shell space remotely from thefirst or second line (in particular at an arbitrary point of the shellof the heat exchanger).

Analogously to this, it is furthermore also possible, in one embodiment,for the second flow connection to connect the gas discharge device tothe shell space remotely from the first or second line (in particular atan arbitrary point of the shell of the heat exchanger).

In one embodiment, it is basically possible for the first and/or thesecond flow connection to also have a buffer accumulator for a gaseousphase of the first medium, and in particular also a compressor and/or avalve (see also below). By means of the compressor, the first medium canbe transported through the respective flow connection. The valve servesfor the adjustment or interruption of the flow of the gaseous phase ofthe first medium.

According to a further aspect of the present invention, an industrialplant is provided which has a heat exchanger according to the inventionand a first component and a first flow connection between the gasdischarge device and the first component of the plant, such that aprocess stream of the plant (e.g. a gaseous phase of the first medium)is introducible from the gas discharge device via the flow connectioninto the first component. In addition or alternatively, the plant mayhave a second component and a second flow connection between the gassupply device and the second component, such that a process stream (e.g.a gaseous phase of the first medium) is withdrawable from the secondcomponent, and introducible into the gas supply device, via the secondflow connection.

The first or the second components may each be an apparatus or a plannedpart of the plant in which the first medium is conducted (e.g. a gasbuffer accumulator and/or a compressor) and/or treated in some otherway. The first and the second component may furthermore each be a plantpart or apparatus from which a gaseous phase of the first medium or aprocess stream is transported to the gas supply device (e.g. via a line)and/or to which a gaseous phase of the first medium is transported fromthe gas discharge device (e.g. via a line). The first component may beidentical to the second component.

According to a further aspect of the present invention, a method foroperating heat a exchanger is proposed, which method uses in particulara heat exchanger according to the invention, wherein a first medium,which has a liquid phase and a gaseous phase, is conducted in a shellspace, surrounded by a shell, of the heat exchanger and indirectlyexchanges heat with a second medium which is conducted in a tube bundlearranged in the shell space, which tube bundle has multiple tubes foraccommodating the second medium, which tubes are helically coiled inmultiple tube layers onto a core tube of the heat exchanger, which tubebundle extends along a longitudinal axis of the shell in the shellspace, wherein the tube bundle has a multiplicity of inner tube layers,which surround the core tube, and a multiplicity of outer tube layers,which surround the inner tube layers and the core tube, and wherein apart of the gaseous phase is discharged out of the shell space from theregion of the inner tube layers (in particular in order to lower apressure in the shell space there), specifically in particular via thegas discharge device, and/or wherein a gaseous phase of the first mediumis supplied into the shell space in the region of the outer tube layers(in particular in order to increase a pressure in the shell spacethere), specifically in particular via the gas supply device.

In one embodiment of the method according to the invention, provision ismade for the discharge and/or the supply of the gaseous phase to becontrolled in open-loop fashion, or in closed-loop fashion in a mannerdependent on an actual pressure distribution or actual temperaturedistribution measured in the shell space (see above). The actualpressure distribution may be measured by means of a multiplicity ofpressure sensors provided in the shell space, or by means of afiber-optic sensor laid through the shell space. Here, in a knownmanner, effects of the pressure on a light-conducting fiber (e.g. glassfiber) are measured. Alternatively or in addition, an actual temperaturedistribution may be measured in the shell space by means of afiber-optic sensor or by means of at least one light-conducting fiber(e.g. glass fiber) of a sensor of said type. It is conceivable tomeasure both an actual temperature distribution and an actual pressuredistribution by means of a fiber-optic sensor.

In particular if an actual temperature distribution is measured by meansof the fiber-optic sensor (and said actual temperature is distributionis used for the closed-loop control of the supply or discharge of thegaseous phase), the fiber-optic sensor or a light-conducting fiber, inparticular glass fiber, of the sensor may be laid along the tubes of thetube bundle, such that a 3D actual temperature distribution can bemeasured.

In the case of closed-loop control, provision may be made in particularfor the heat exchanger to control the supply and/or discharge of thegaseous phase in closed-loop fashion such that the actual pressuredistribution in the shell space is approximated to a setpoint pressuredistribution or such that the actual temperature distribution in theshell space is approximated to a setpoint temperature distribution,wherein, in particular, the pressure of the setpoint pressuredistribution is in each case constant in a radial direction of the tubebundle, specifically in particular at least at a defined height of theshell space (e.g. at the level of the discharge and/or supply of thegaseous phase) or in a defined shell space section along thelongitudinal axis of the shell. In the same way, it is in particular thecase that the temperature of the setpoint temperature distribution isconstant in a radial direction, specifically in particular at least at adefined height of the shell space (e.g. at the height of the dischargeand/or supply of the gaseous phase) or in a defined shell space sectionalong the longitudinal axis of the shell.

Preferably, over the entire length of the tube bundle along thelongitudinal axis, a part of the gaseous phase is discharged from theregion of the inner tube layers via a multiplicity of inlet openings,and/or the gaseous phase of the first medium is, in the region of theouter layers, supplied via a multiplicity of outlet openings, such that,in particular over the entire length of the tube bundle, the actualpressure distribution or the actual temperature distribution isapproximated to a setpoint pressure distribution or setpoint temperaturedistribution respectively, in the case of which the pressure or thetemperature respectively is in each case constant in a radial directionand follows a predefined profile in an axial direction (that is to sayalong the longitudinal axis).

Finally, according to a further aspect of the present invention, a heatexchanger for the indirect exchange of heat between a first medium,which has a liquid phase and a gaseous phase, and a second medium isdisclosed, having

-   -   a shell which surrounds a shell space and which extends along a        longitudinal axis, wherein the shell space serves for        accommodating the first medium, and    -   a tube bundle which is arranged in the shell space and which has        multiple tubes for accommodating the second medium, which tubes        are helically coiled in multiple tube layers onto a core tube of        the heat exchanger, which tube bundle extends along the        longitudinal axis of the shell in the shell space, wherein the        tube bundle has a multiplicity of inner tube layers, which        surround the core tube, and a multiplicity of outer tube layers,        which surround the inner tube layers and the core tube,    -   wherein the heat exchanger is designed to        -   discharge a part of the gaseous phase out of the shell space            from the region of the inner tube layers via a gas discharge            device, and/or            -   supply a gaseous phase of the first medium into the                shell space in the region of the outer tube layers via a                gas supply device.

A heat exchanger of said type may likewise be refined by means of thefeatures or embodiments described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and advantages of the invention shall be elucidatedthrough the following figure description of an exemplary embodiment byreference to the figures, in which:

FIG. 1 shows embodiments of the heat exchanger according to theinvention in which a gaseous phase is withdrawable from the shell spacein the region of the innermost tube layer via the core tube;

FIG. 2 shows further embodiments of the heat exchanger according to theinvention in which a gaseous phase is introducible into the shell spacein the region of the outermost tube layer via the skirt;

FIG. 3 shows a further embodiment, in which both the supply and thedischarge of the gaseous phase as per FIGS. 1 and 2 is possible; and

FIG. 4 shows a modification of the embodiment shown in FIG. 3;

FIG. 5 shows a perspective view of the tube bundle of the heat exchangershown in FIGS. 1 to 4;

FIG. 6 shows a multiplicity of different embodiments with regard to flowconnections of the gas supply or gas discharge device to components ofthe heat exchanger or of a plant in which the heat exchanger may beincorporated; and

FIG. 7 further embodiments with regard to flow connections of the gassupply or gas discharge device to components of the heat exchanger or ofa plant in which the heat exchanger may be incorporated.

FIGS. 1 to 4 each show an embodiment of a coiled heat exchanger 1according to the invention. In the respective embodiment, the coiledheat exchanger 1 has in each case a shell 5, which is preferablycylindrical at least in sections and which surrounds a shell space 6 ofthe heat exchanger 1, and a tube bundle 3, which is arranged in theshell space 6 and which may have multiple tubes 30 which may behelically coiled on a core tube 300, wherein the core tube 300 isarranged in particular coaxially with respect to a longitudinal axis zof the heat exchanger 1 or of the shell 5, along which longitudinal axisthe shell 5 extends.

The tube 30 of the tube bundles 3 are in particular coiled helicallyonto the core tube 300 in multiple tube layers, wherein the individualtube layers are supported against one another by means of spacerelements 10, such that the entire weight of the tube layers canultimately be dissipated through the core tube 300. The tube bundle 3therefore correspondingly has, in a radial direction R, an innermosttube layer 4 aa, which is arranged adjacent to the core tube 300, and anoutermost tube layer 4 bb in the radial direction R. The tube layers ofthe tube bundle 3 may in this case be divided into inner tube layers 4 aand outer tube layers 4 b in accordance with the definition given above.

The tube bundle 3 of FIGS. 1 to 4 may for example be formed as per FIG.5, wherein here, for the sake of clarity, the gas discharge device 43and the gas supply device 53 (see below) are not shown.

The said longitudinal axis z runs preferably parallel to the vertical.Furthermore, the coiled heat exchanger 1 has an in particularcylindrical skirt 7, which surrounds the tube bundle 3. Here, the skirt7 has an inner side 7 a, which faces toward the tube bundle 3, inparticular the outermost tube layer 4 bb, and an outer side 7 b, whichis averted from the inner side 7 a and which faces toward the shell 5.The skirt 7 serves for preventing a bypass flow in the shell space 6past the tube bundle 3.

A liquid phase F of a first medium M is applied to the tube bundle 3from the top by means of a liquid distributor V, which first medium thencomes into indirect heat-exchanging contact with a second medium M′conducted in the tubes 30 of the tube bundle 3. The liquid distributor Vmay have multiple arms A, which are fed with liquid F for example viathe core tube 300.

For the sake of clarity, the liquid distributor V is shown only in FIG.1, but is also provided in the embodiments as per FIGS. 2 to 5 andconfigured in the manner of FIG. 1.

In the case of a coiled heat exchanger 1, an uneven distribution of theliquid phase F of the first medium M may arise, in the case of which theliquid phase F is forced outward toward the shell 5. This gives rise, inparticular in a radial direction R of the tube bundle 3, to a pressuredrop in the direction of the shell 6 or a corresponding temperaturedistribution, which is detrimental to the efficiency of the heatexchanger 1.

Here, the respective radial direction R is perpendicular to thelongitudinal axis z or to the core tube 300, wherein the longitudinalaxis z coincides with the axial direction of the tube bundle 3.

To compensate such a pressure drop of an actual pressure distribution Pwhich is measurable in the shell space, in a first embodiment, shown inFIG. 1, of the heat exchanger 1 according to the invention, provision ismade for the heat exchanger 1 to be designed to discharge a part of thegaseous phase G out of the shell space 6 from the region of the innertube layers 4 a, 4 aa by means of a gas discharge device 43. Here, FIG.1 illustrates two alternative variants, which will be described in moredetail below.

In particular, in a first variant as per FIG. 1, the gas dischargedevice 43 of the heat exchanger 1 has at least one discharging flow path40 for the gaseous phase G with an inlet opening 41 arranged in theshell space 6 in the region of the inner tube layers 4 a, wherein, forexample, the at least one discharging flow path 40 is formed by a tube30 of an inner tube layer 4 a, in particular of an innermost tube layer4 aa of the tube bundle 3.

As an alternative to this, the heat exchanger 1 or the gas dischargedevice 43 may, in a second variant (cf. FIG. 1), have a discharging flowpath 40 for the gaseous phase G, which discharging flow path runs atleast in sections in an interior space of the core tube 300 and has aninlet opening 41 arranged in the shell space 6 in the region of theinner tube layers 4 a, which inlet opening is in the present case formedfor example in a wall of the core tube 300.

Thus, by means of the discharging flow path 40, at least a part of thegaseous phase G of the first medium M can be withdrawn from the shellspace, specifically in the present case in the region of the innermosttube layer 4 aa. In this way, at the withdrawal point, that is to say atthe inlet opening 41, the actual pressure distribution P generated inFIG. 1 can be generated, which has an as far as possible constantpressure in a radial direction R. Such withdrawal points or inletopenings 41 may, in FIG. 1, be provided along the entire length of thetube bundle 3 along the longitudinal axis z, in order to realize, forthe entire tube bundle 3, a pressure which is as far as possibleconstant in a radial direction R or a temperature which is as far aspossible constant in a radial direction R. Closed-loop control of thedischarge of the gaseous phase G may be realized by means of a valve 8.This applies in particular both to the discharging flow path 40 whichhas said tube 30 of the inner or innermost tube layer 4 a, 4 aa (firstvariant), and to the discharging flow path 40 which runs at least insections in the interior space of the core tube 300 (second variant).For the sake of simplicity, the valve 8 is shown in FIG. 1 only for theflow path 40 running in the interior space of the core tube 300.

The valve 8 is preferably adjusted such that an actual temperaturedistribution measured in the shell space 6 is approximated to a desiredsetpoint temperature distribution. Alternatively, the closed-loopcontrol may also be performed such that a measured actual pressuredistribution is approximated to a desired setpoint pressuredistribution. The temperature or the pressure may be measured in theshell space for example in a known manner by means of a light-conductingfiber L or other suitable sensors (see also above). A light-conductingfiber L may for example be laid along the tubes 30, and is schematicallyindicated in FIG. 1.

FIG. 2 shows a modification of the embodiment shown in FIG. 1, wherein,by contrast to FIG. 1, provision is made for the gaseous phase G not tobe withdrawn from the shell space 6 in the region of the inner tubelayers 4 a, 4 aa but introduced into the shell space 6 in the region ofthe outer tube layers 4 b, in particular in the region of the outermosttube layer 4 b.

For this purpose, the heat exchanger 1 as per FIG. 2 has a gas supplydevice 53 with at least one supplying flow path 50 for the gaseous phaseG, which in a first variant runs on the outer side 7 b of the skirt 7,and within the shell space 6. It is self-evidently also conceivable fora flow path 50 of said type to be laid outside the shell 5 and to thenlead through the shell 5 and the skirt 7. Furthermore, it isalternatively possible, in a second variant which is likewise shown inFIG. 2, for a flow path 50 of said type to be formed by a tube 30 of anouter tube layer 4 b of the tube bundle 3, in particular by a tube 30 ofan outermost tube layer 4 bb of the tube bundle 3.

As shown in FIG. 2, the at least one supplying flow path 50 has anoutlet opening 51 which, in the present case, is formed in the skirt 7(or alternatively in said tube 30 of the outer or outermost tube layer 4b, 4 bb), such that the introduced gaseous phase G in the present caseimpinges on the outermost tube layer 4 bb. In this way, in particular inthe region of the outer tube layers 4 b, the pressure in the shell space6 can be increased, such that, overall, a pressure P which is as far aspossible constant in a radial direction R is realized as a result. Also,in FIG. 2, it is self-evidently possible for multiple inlet openings 51to be provided along the longitudinal axis z, such that, as alreadydescribed above on the basis of FIG. 1, the pressure can be positivelyinfluenced over the entire length of the tube bundle along thelongitudinal axis z. Also, in FIG. 2, closed-loop control of the supplyof the gaseous phase G can be performed by means of a valve 8,specifically in particular both for the supplying flow path 50 which hassaid tube 30 of the outer or outermost tube layer 4 b, 4 bb andalternatively for the supplying flow path 50 which runs on the outerside 7 b of the skirt 7. For the sake of simplicity, the valve 8 isshown in FIG. 2 only for the flow path 50 running on the outer side 7 bof the skirt 7.

The valve 8 is preferably adjusted such that an actual pressuredistribution P measured in the shell space 6, or alternatively ameasured actual temperature distribution, is approximated to acorresponding setpoint pressure distribution or setpoint temperaturedistribution.

Furthermore, as per FIG. 3, it is self-evidently also possible for therespective embodiments as per FIG. 1 and FIG. 2 to be combined, suchthat a gaseous phase G of the first medium M can be both withdrawn fromand supplied to the shell space 6.

In this regard, FIG. 4 shows a modification of the embodiment shown inFIG. 3, wherein here, for the closed-loop control of the discharge ofthe gaseous phase G via the at least one discharging flow path 40 andfor the closed-loop control of the supply of the gaseous phase G via theat least one supplying flow path 50, provision is made for the two flowpaths 40, 50 to be connected in terms of flow by means of a compressor 9which is controllable in closed-loop fashion, such that a gaseous phaseG which is withdrawn from the shell space 6 in the region of the innertube layers 4 a is variably compressible by means of the compressor 9and introducible into the shell space 6 again in the region of the outertube layers 4 b. Here, the gaseous medium G is thus conducted in acircuit. For the sake of simplicity, the compressor 9 is shown in FIG. 4only for the flow path 40 running in the interior space of the core tube300 and the flow path 50 running on the outer side 7 b of the skirt 7,though said compressor may self-evidently also be used if the two flowpaths 40, 50 are formed by a tube 30 of an inner or innermost tube layer4 a, 4 aa and by a tube 30 of an outer or outermost tube layer 4 b, 4bb.

Instead of closed-loop control of the supply and discharge of thegaseous phase G, it is self-evidently also possible in FIGS. 1 to 4 foropen-loop control of said supply or discharge of the gaseous phase G tobe provided.

Instead of additional flow paths 40, 50 which, in some embodiments asper FIGS. 1 to 4, are used in addition to the tube bundle 3 to withdrawa gaseous phase G from the shell space 6 in spatially targeted fashionor introduce a gaseous phase G into the shell space 6 in spatiallytargeted fashion in order to influence pressure or temperature profilesin targeted fashion, it is self-evidently basically also possible, asdescribed above, for example, to use individual tubes 30 of the tubebundle 3 which are situated at the desired point, for example a tube 30from the outermost tube layer 4 bb for introducing the gaseous phase Gor a tube 30 from the innermost tube layer 4 aa for discharging gaseousphase G.

In addition to the possibilities, already presented above, of a flowconnection of the gas discharge device 43 and gas supply device 53 tocomponents of the heat exchanger 1, FIGS. 6 and 7 show furtherembodiments of a heat exchanger 1 according to the invention or of aplant 2 which has the heat exchanger 1, which embodiments relate to theinterconnection of the gas discharge and gas supply device 43, 53.

Accordingly, as per FIG. 6, provision may be made for the heat exchanger1 to have a first line 411, via which the first medium M on the shellside is fed (in particular in two-phase form) for example into an uppersection of the heat exchanger 1 or into the shell space 6.

Furthermore, the heat exchanger 1 may have a second line 511, via whichthe first medium M on the shell side can be withdrawn from the shellspace 6 or heat exchanger. The second line 511 may for example beprovided at a lower section of the heat exchanger 1.

With regard to the line 411 or 511, provision may be made for the gasdischarge device 43 to be connected via a first flow connection 410 tothe first line 411, such that a part of a gaseous phase G of the firstmedium M can be withdrawn from the shell space 6 of the heat exchanger1, and fed into the first line 411, via the gas discharge device 43 andthe first flow connection 410.

As an alternative to this, the gas discharge device 43 may be connectedvia a first flow connection 410 to the second line 511, such that a partof the gaseous phase G of the first medium M can be withdrawn from theshell space 6 of the heat exchanger 1, and fed into the second line 511,via the gas discharge device 43 and the first flow connection 410.

Furthermore, it is also possible for the gas supply device 53 to beconnected via a second flow connection 510 to the first line 411, suchthat a part of the gaseous phase G of the first medium M can be fed fromthe first line 411 into the gas supply device 53 via the second flowconnection 510.

As an alternative to this, it is possible for the gas supply device 53to be connected via a second flow connection 510 to the second line 511,such that a part of the gaseous phase G of the first medium M can be fedfrom the second line 511 into the gas supply device 53 via the secondflow connection 510.

As per FIG. 6, the first and the second flow connection 410, 510 mayhave a gas buffer accumulator 90, a compressor 9 and in particular avalve 8, by means of which the flow of the gaseous phase G of the firstmedium M can be adjusted or interrupted. Here, the heat exchanger 1,together with the respective gas buffer accumulator 90, compressor 9 andvalve 8, thus forms an industrial plant 2 or a part of such a plant 2,in which the first medium M constitutes a process stream. If the heatexchanger 1 or the plant 2 is, for example as per one exemplaryembodiment, used for the liquefaction of natural gas, the first medium Mon the shell side is a mixture of refrigerants. The first medium M maybasically also be a process stream from another plant part of the plant2.

With regard to FIG. 6, it is to be noted that, for the sake ofsimplicity, FIG. 6 combines different embodiments in one figure, that isto say shows all possible flow connections 410 and 510 between the gassupply and the gas discharge device 53, 43 and the first and the secondline 411, 511, wherein, however, the gas discharge device 43 is inparticular connected only via one of the two stated flow connections 410to the first line 411 and to the second line 511. The same applies inparticular to the gas supply device 53 with regard to the two flowconnections 510 that are shown.

Furthermore, as per FIG. 7, provision may also be made for the gasdischarge device 43 to be connected to the shell space 6 of the heatexchanger 1 at an arbitrary point (in particular remotely from the twolines 411, 511) via the first flow connection 410, such that the firstmedium M is withdrawable from the shell space 6, and introducible intothe shell space 6 again, via the gas discharge device 43 (and inparticular via the valve 8, the gas buffer accumulator 90 and thecompressor 9). Similarly, as per FIG. 7, the gas supply device 53 maylikewise be connected to the shell space 6 of the heat exchanger 1 at anarbitrary point (in particular remotely from the two lines 411, 511) viathe second flow connection 510, such that the first medium M iswithdrawable from the shell space 6 via the second flow connection 510(in particular via the gas buffer accumulator 90, the compressor 9 andthe valve 8), and introducible into the shell space 6 again, via the gassupply device 53. The flow connections 410, 510 shown in FIGS. 6 and 7may self-evidently also be combined with one another in any desiredmanner.

If additional flow paths 40, 50 are used, the present invention has thefurther advantage that existing coiled heat exchangers can beparticularly easily retrofitted with said flow paths 40, 50, such that,in this case, too, a performance improvement can be achieved.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding description, utilize the present invention toits fullest extent. The preceding preferred specific embodiments are,therefore, to be construed as merely illustrative, and not limitative ofthe remainder of the disclosure in any way whatsoever.

In the foregoing and in the examples, all temperatures are set forthuncorrected in degrees Celsius and, all parts and percentages are byweight, unless otherwise indicated.

The entire disclosures of all applications, patents and publications,cited herein and of corresponding European application No. 17020286.5,filed Jul. 10, 2017, are incorporated by reference herein.

The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention and, withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

List of reference numerals  1 Heat exchanger  3 Tube bundle 4a, 4aaInner tube layer 4b, 4bb Outer tube layer  5 Shell  6 Shell space  7Skirt  7a Inner side  7b Outer side  8 Valve  9 Compressor 10 Spacer 30Tubes 43 Gas discharge device 40 Discharging flow path 41 Inlet opening53 Gas supply device 50 Supplying flow path 51 Outlet opening 300  Coretube 410  First flow connection 411  First line 510  Second flowconnection 511  Second line 90 Gas buffer store F Liquid phase G Gaseousphase M First medium  M′ Second medium P Actual pressure distribution LLight-conducting fiber, or fiber-optic sensor R Radial direction ZLongitudinal axis

1. Heat exchanger (1) for the indirect exchange of heat between a firstmedium (M), which has a liquid phase (F) and a gaseous phase (G), and asecond medium (W), having a shell (5) which surrounds a shell space (6)and which extends along a longitudinal axis (z), wherein the shell spaceserves for accommodating the first medium, a tube bundle (3) which isarranged in the shell space (6) and which has multiple tubes (30) foraccommodating the second medium (M′), which tubes are helically coiledin multiple tube layers onto a core tube (300) of the heat exchanger(1), which tube bundle extends along the longitudinal axis (z) of theshell (5) in the shell space (6), wherein the tube bundle (3) has amultiplicity of inner tube layers (4 a, 4 aa), which surround the coretube (300), and a multiplicity of outer tube layers (4 b, 4 bb), whichsurround the inner tube layers (4 a, 4 aa) and the core tube (300),characterized in that the heat exchanger (1) is designed to discharge apart of the gaseous phase (G) out of the shell space (6) from the regionof the inner tube layers (4 a, 4 aa) via a gas discharge device (43),wherein the gas discharge device (43) of the heat exchanger (1) has atleast one discharging flow path (40) for the gaseous phase (G) with aninlet opening (41) arranged in the shell space (6) in the region of theinner tube layers (4 a), and wherein the at least one discharging flowpath (40) is formed by a tube (30) of an inner tube layer (4 a) of thetube bundle (3), and/or supply a gaseous phase (G) of the first medium(M) into the shell space (6) in the region of the outer tube layers (4b, 4 bb) via a gas supply device (53).
 2. Heat exchanger according toclaim 1, characterized in that the heat exchanger (1) has a skirt (7)which surrounds the tube bundle (3) and which surrounds the outer tubelayers (4 b, 4 bb).
 3. Heat exchanger according to claim 1,characterized in that the gas supply device (53) of the heat exchanger(1) has, for the gaseous phase (G), at least one supplying flow path(50) which has an outlet opening (51) arranged in the region of theouter tube layers (4 b) in the shell space (6).
 4. Heat exchangeraccording to claim 3, characterized in that the at least one supplyingflow path (50) is, at least in sections, led on an outwardly pointingouter side (7 b) of the skirt (7) or through a tube (30) of an outertube layer (4 b) of the tube bundle, in particular through a tube (30)of an outermost tube layer (4 bb) of the tube bundle (3).
 5. Heatexchanger according to claim 1, characterized in that the gas dischargedevice (43) of the heat exchanger (1) has multiple discharging flowpaths (40) for the gaseous phase (G) of the first medium (M) with ineach case one inlet opening (41), wherein the inlet openings (41) areeach arranged in the shell space (6) in the region of the inner tubelayers (4 a), and wherein, in particular, the inlet openings (41) arearranged at different heights along the longitudinal axis (z).
 6. Heatexchanger according to claim 1, characterized in that the gas supplydevice (53) of the heat exchanger (1) has multiple supplying flow paths(50) for the gaseous phase (G) of the first medium (M) with in each caseone outlet opening (51), wherein the outlet openings (51) are eacharranged in the region of the outer tube layers (4 b) in the shell space(6), and wherein, in particular, the outlet openings (51) are arrangedat different heights along the longitudinal axis (z).
 7. Heat exchangeraccording to claim 1, characterized in that the heat exchanger (1) isdesigned to control the supply of the gaseous phase (G) via the gassupply device (53) and/or the discharge of the gaseous phase (G) via thegas discharge device (41) in open-loop fashion, or in closed-loopfashion in a manner dependent on an actual pressure distribution (P), oractual temperature distribution, measured in the shell space (6). 8.Heat exchanger according to claim 1, characterized in that the at leastone discharging flow path (40) has a valve (8) for the open-loop orclosed-loop control of the discharge of the gaseous phase (G), and/or inthat the at least one supplying flow path (50) has a valve (8) for theopen-loop or closed-loop control of the supply of the gaseous phase (G).9. Heat exchanger according to claim 1, characterized in that the atleast one discharging flow path (40) is connected in terms of flow via acompressor (9) to the at least one supplying flow path (50).
 10. Heatexchanger according to claim 1, characterized in that the individualtube layers (4 a, 4 b) bear against one another via spacers (10). 11.Heat exchanger according to claim 1, characterized in that the core tube(300) accommodates the load of the tubes (30) of the tube bundle (3).12. Plant (2) having a heat exchanger (1) according to claim 1, andhaving a first component (90) and a first flow connection (410) betweenthe gas discharge device (43) and the first component (90) of the plant,such that a process stream (M) of the plant, which has in particular agaseous phase (G) of the first medium (M), is introducible from the gasdischarge device (41) via the flow connection (410) into the firstcomponent (90), and/or in that the plant (2) has a second component (90)and a second flow connection (510) between the gas supply device (53)and the second component (90), such that a process stream (M) of theplant (2), which has in particular a gaseous phase (G) of the firstmedium (M), is withdrawable from the second component (90), andintroducible into the gas supply device (53), via the second flowconnection (510).
 13. Method for operating a heat exchanger (1)according to claim 1, wherein a first medium (M), which has a liquidphase (F) and a gaseous phase (G), is conducted in a shell space (6),surrounded by a shell (5), of the heat exchanger (1) and indirectlyexchanges heat with a second medium (M′) which is conducted in a tubebundle (3) arranged in the shell space (6), which tube bundle hasmultiple tubes (30) for accommodating the second medium (M′), whichtubes are helically coiled in multiple tube layers (4 a, 4 b) onto acore tube (300) of the heat exchanger (1), which tube bundle extendsalong a longitudinal axis (z) of the shell (5) in the shell space (6),wherein the tube bundle (3) has a multiplicity of inner tube layers (4a), which surround the core tube (300), and a multiplicity of outer tubelayers (4 b), which surround the inner tube layers (4 a) and the coretube (300), and wherein a part of the gaseous phase (G) is dischargedout of the shell space (6) from the region of the inner tube layers (4a, 4 aa), and/or wherein a gaseous phase (G) of the first medium (M) issupplied into the shell space (6) in the region of the outer tube layers(4 b, 4 bb).
 14. The method as claimed in claim 13, wherein thedischarge and/or the supply of the gaseous phase (G) is controlled inopen-loop fashion, or in closed-loop fashion in a manner dependent on anactual pressure distribution (P), or actual temperature distribution,measured in the shell space (6).